Viessmann VITODENS 200-W Operating Instructions For The System User page 5

Safety instructions
For your safety
(cont.)
Danger
The simultaneous operation of the
boiler and appliances that extract
air to the outside can result in life
threatening poisoning due to a
reverse flow of flue gas.
Take suitable steps to ensure an
adequate supply of combustion air.
If necessary, contact your contrac-
tor.
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